Questions tagged [vector]
Mathematical vectors, operations on vectors and vectorized programming.
581
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Convert a polynomial to a vector
I am trying to transform a generated polynomial terms into a vector, I used the command 'MonomialList',
...
- 11
0
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1
answer
46
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Total Spin Matrix Squared (Casimir Operator)
I am trying to get Mathematica to compute the Casimir operator of a 4 particle system of spin $1/2$ fermions. I have the following code which does not do what I would like it to.
...
- 137
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0
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65
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How to matricize a vector?
I am wondering how to represent a vector as a matrix, using specified dimensions. For example, MatrixForm[{a, b, c, d}] gives me a column vector. But I would want ...
0
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1
answer
86
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How do I find the unit vector in the direction of the minimal rate of change?
A ball falls on the surface $x^4 z+x^9 y^2+y^2 z^3=65$ at the point (-1,-3,2). How do I find a three-dimensional unit vector in the direction that the ball will begin to roll. I know that the ball ...
- 85
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2
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137
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How to subtract a list from certain sublists of a list? [closed]
I have a problem in doing an operation on this vector
{{2,3},{3,4},{5,6}}-{1,1}
I want to minus this to get the result
...
- 49
1
vote
1
answer
146
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Solving equation set with vectors
I have six unit vectors in real $3$D space
v1,v2,v3,v4,v5,v6;
Represent the dot product between some of the vectors as the Cos ...
- 270
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1
answer
62
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0
votes
1
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38
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Reduce expressions into (simplified) matrix and vector forms
I have some computation that results in a rather complicated looking expression that could be much simplified by converting it into matrix or vector expressions. For example, instead of ...
- 206
2
votes
1
answer
94
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Dot Product of Vector with matrix components
In Physics it's common to write matrices in vector components to simplify notation. This commonly occures with the pauli vector $\vec\sigma = \begin{pmatrix}\sigma_1 & \sigma_2 & \sigma_3\end{...
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61
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Finding the Curvature of the path of a particle
How do I find the curvature of the vector when t=5?
The function is:
v[t_] := {2 t^4 + 2, 6 t^3 + 1, 3 t^2 + 4}
- 85
2
votes
0
answers
61
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Finding the Torsion given a vector r[t]
How do I find the torsion of a vector?
The function is:
r[t_]:={Sin[7t],t^4,Cos[7t]}
- 85
1
vote
2
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74
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How would I find the Binormal vector? [duplicate]
How would I find the Binormal vector if r[t_]:={sin(7t),t^4,cos(7t)} in Mathematica?
This is the Mathematica code I have:
...
- 85
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39
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I am searching for the Eigen stuff of a non linear transformation
I have a slightly odd problem I have been working on as part of a project on probability models. The full problem itself is not relevant but here is where I am stuck.
I have a 6D space $P$, where all ...
- 111
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40
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How would you write a electric field in cylindrical coordinates?
I am new to Mathematica and I am trying to automate the process of finding electric and magnetic fields for TE and TM modes in a cylindrical superconducting cavity. I could not find documentation ...
4
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2
answers
263
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Is it possible to solve vector equations?
For example if we define parametric line segment
curve1[t_, p1_, p2_] := t*p2 + (1 - t)*p1;
where p1 and ...
- 725
2
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1
answer
115
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Writing a system of ODEs in vector form
I have the following system:
$\frac{dx}{dt} = p_x \\ \frac{dy}{dt} = p_y \\ \frac{dp_x}{dt}=-\frac{\partial V}{\partial x} \\ \frac{dp_y}{dt}=-\frac{\partial V}{\partial y}$
,where $V(x,y) = \frac{1}{...
- 199
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1
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68
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How can I remove the attributes "Orderless" from function Times stably and reliably?
Recently I have been doing some algebra of partitioned matrices, where product like below is common:
where $A_{11}, A_{12}, X, Y$ are all partitioned matrix blocks thus all are matrices in essence.
...
- 289
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1
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90
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dot product and norm [closed]
Can you solve the following problem in mathematica program? Thank you.
Let x=(x1,x2,x3),y=(y1,y2,y3) and ⟨x,y⟩=x1y1+2x2y2+x3y3 be an inner product in a three-dimensional real vector space.
Define the ...
- 13
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60
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Can I use assumptions to declare a variable's type?
I'm trying to declare $P$ as a vector. I searched for a while, the closest way seems to be Assumptions:
...
- 174
2
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0
answers
90
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Bug with ListVectorPlot in 12.3.1?
Bug fixed in 13.0.0
The documentation shows that result of
...
- 271
2
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0
answers
47
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Why does the dot product between a matrix and a vector not work? [duplicate]
Executing this code:
...
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3
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119
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How can I do operations in this basis (using matrices)? [closed]
Let's define
$u=t+1/2$
$v=t-1/2$
Now, I have vectors in the basis $e_n=u^n-v^n$, I want to apply functions to such expressions, but as a result get expressions in the same basis again.
For instance, $...
- 2,721
1
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0
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40
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How to generate a Gaussian random velocity field
Let us assume we have a 2-dimensional velocity field $\textbf{u}=(u_x,u_y)$ defined via its stream function $\psi(\textbf{x})$ as
\begin{cases}
u_x=\partial_y\psi(\textbf{x}) \\
u_y=-\partial_x\psi(\...
- 63
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74
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piecewise vector field and composition of piecewise functions
I have the following vector field
...
- 41
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2
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56
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FindRoot with vector function
I have trouble with FindRoot for vector variables, I have search MMA SE find a solution. in Szabolcs‘s code, Vector FindRoot ...
- 445
1
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1
answer
55
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Why doesn't my code evaluate element of a vector at a given t?
I have written a code to solve the Shrodinger equation for a particular three level siystem in two ways: the first way I defined three functions C1[t], C2[t], C3[t] and I solved three ODEs;
the ...
- 31
1
vote
1
answer
49
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Interpolate function against time
I have two vectors called lammdaWind11 and timeWind11. They are of size 51*1. I have interpolted each one independently as
...
- 115
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0
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53
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velocity four-vector definition by xAct
I want to define the velocity vector by the following relation and evaluate the norm of the vector by using the Minkowski metric.
I have defined the tensor x (position tensor) in xAct, but I don't ...
0
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0
answers
58
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Is it possible to generate a random vector space in Mathematica?
The idea is that I’d like to try to use Mathematica to work through proofs. So if a proof says, “Let there be a vector space V…”, I would like to see a concrete representation of that vector space in ...
- 101
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votes
1
answer
49
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Plotting two vector fields $\vec V_1=-y\hat i+x \hat j$ and $\vec V_1=2\vec V_1$ on the same plot
I want to compare how two vector fields $\vec V_1=-y\hat i+x \hat j$ and $\vec V_1=2\vec V_1=2(-y\hat i+x \hat j)$ various concentric circles $x^2+y^2=a^2$ with $a^2=1,2,3$ etc. I can plot them ...
- 157
1
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3
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67
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Drawing circles on top of a vector field drawn using VectorPlot
I am using the command
VectorPlot[{{y, -x}}, {x, -4, 4}, {y, -4, 4}]
to plot the vector field $\vec{V}=y\hat{i}-x\hat{j}$. On top of this, I need to draw circles of radii $1,2,3...$, etc. I am no ...
- 157
0
votes
2
answers
81
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How to find a matrix satisfying following equation
I have a $N \times 1$ vector $F(t)$ for $0\leq t \leq 1$.
I want to find a $N\times N$ Matrix $C$ (a real-valued matrix) satisfying the following equation:
$$\int_0^t F(t_0)dt_0= C.F(t)$$
If it ...
- 483
3
votes
0
answers
57
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Using ColorFunction Rasterizes the plot
When I make a simple plot using ColorFunction, the Mathematica rasterize the plot. Is anyone else having this issue? Does anyone know a way to avoid this?
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- 31
1
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1
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118
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how to rotate a 3D vector around arbitrary axis
I have three vectors red, blue, and green and their origins are at (x,y,z) where red and blue are perpendicular and can be rotated together in the x-y plane by ...
- 2,977
1
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1
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83
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Generate a normalized Haar-random vector
What is the procedure to generate a random qutrit quantum state?
That is, I want to generate a $3 \times 1$ vector $u$ such that $u$ is generated by a Haar random $3 \times 3$ unitary $U$ multiplied ...
- 165
1
vote
4
answers
103
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multi-dimensional interpolating function evaluation and extract dimension
I have an interpolating function which output dimension is greater than 1, so it's a vector. I get it as the result of a NDSolveValue. The problem is that I'm not able to Evaluate it. I would obtain ...
1
vote
1
answer
48
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How to make a vector of elements the pattern of a function?
if I have an expression that contains a lot of symbolic elements and I would want to make it a function of the vector containing all the elements I've found a solution based on rule delayed:
...
3
votes
1
answer
56
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Plotting translated vector fields from user-defined functions
I have two time- and space-dependent vector fields, one which is:
$\mathbf A(x,y,t) = -y \, t \, \hat{\mathbf x} + x \, t \, \hat{\mathbf y}, \tag 1$
and another $\mathbf B(x,y,t)$ which is $\mathbf A$...
- 433
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0
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35
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How To Define Indexed Vectors
I have to define two 2-D vectors to be multiplied by a matrix and multiplied by several Clebsch-Gordan coefficients. Below are my definitions and my attempt at computing the sum.
...
- 61
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0
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36
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Looking for a starting point to solve a PDE with vector-coefficients
I am looking for a good source for Mathematica in order to solve a PDE with vector coefficients.
I have found this:
https://reference.wolfram.com/language/FEMDocumentation/tutorial/SolvingPDEwithFEM....
- 235
2
votes
1
answer
118
views
Using Curl and Grad in cylindrical coordinates gives different result than in Cartesian
I am doing a quite elementary calculation to verify
$$
\vec \nabla\cdot V = \vec\nabla \times \vec A
$$
Where $V$ is just some scalar function in $\rho$, $\phi$ and $z$ and $A$ is defined as
$$
...
7
votes
2
answers
212
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Imposing breaks in contours in a ContourPlot without rasterization
In this question, we are asked to compute breaks in the contours of a ContourPlot so as to place contour labels (values) atop the colored boundaries rather than the ...
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2
votes
3
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177
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add columns of list {a0,b0} to columns of list {{a0,b0} ,{a1,b1} ,{a2,b2} ...{ax,bx} } [closed]
If I want to add the columns of {1,2} to each of the columns of say
{{1,2},{3,2},{4,2}}
resulting in
{{2, 4}, {4, 4}, {5, 4}}
How would I do this? and for any ...
- 325
0
votes
2
answers
118
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How can I create and plot (in the same diagram) 1000 different vectors in Mathematica? [closed]
I'm new to Mathematica and I got stuck. Also, I'm not a programmer, so I would like to ask the following question.
I want to make 1000 different vectors, of which everyone contains 55 random elements. ...
0
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0
answers
55
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Steam plotting of vector field showing empty output
I am trying to plot the stream lines for a vector field function, whose definition is exported to the wdx file uploaded here. The following simple code returns an empty plot:
...
- 238
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0
answers
56
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Grouping vectors into groups of 3 by attribute
Three groups are given, each with eight $3 \times3$-vectors:
...
- 1,626
0
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1
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96
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How do I set an element of an already-defined vector function to some expression?
I'm defining a vector whose elements depend on time, i.e. I'm defining a real vector function of real elements that depend on the real scalar time variable. The vector function is named ...
- 433
4
votes
4
answers
253
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Is there an easy way to copy a TableForm column and convert it into a vector?
Is there an easy way to take a column output from a TableForm command, like this:
...
- 621
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1
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125
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Derivative matrix by vector in Mathematica
This is an excerpt from the article https://www.sciencedirect.com/science/article/abs/pii/S0094114X10000418.
How do I write this using vector-matrix operations (...
- 1,626
0
votes
1
answer
62
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Derivative of Kronecker product by vector in Mathematica
I'm struggling with the following problem. It is necessary to find the derivative expression with respect to the vector $u$:
$r(u,v)=[(u-v)(u-v)^T]\begin{pmatrix}
1\\
1\\
1
\end{pmatrix}=[(u-v)\otimes ...
- 1,626